National Geographic : 1908 Mar
MARKING THE ALASKAN BOUNDARY Some of the difficulties of triangulation. Climbing an almost vertical cliff by a rope. This cliff is almost Ioo feet high, and affords the only means to reach the summit. The man on the rope has a theodolite on his back. This ascent had to be made five times before the necessary observations were completed. Photo by E. R. Martin, Alaskan Boundary Survey.